Telephone system.



H. P. GLAUSBN. TELEPHONE SYSTEM. APPLIOATION FILED MAR.17, 19oz.

Patented May 16, 1911.

UNITED STATES PATENT OFFICE.

HENRY I. CLAUSEN, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS,TO STROMBERG-CARLSON TELEPHONE MANUFACTURING COMPANY, OF ROCHESTER, NEWYORK, A. CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented May 16, 1911.

Application filed March 17, 1902. Serial No. 98,462.

To all whom it may concern:

Be it known that I, HENRY P. CLAUSEN, a citizen of the United States ofAmerica, and resident of Chicago, Cook county, Illinois, have invented acertain new and useful Improvement in Telephone Systems, of which thefollowing is a'specification.

My invention relates to telephone systems in which complete metalliccircuits are employed between the substation and the central exchange,and in which the current, both for talking and signaling purposes, issupplied from a battery or other suitable source at the central station.In systems of this character a line signal, preferably in the nature ofa small incandescent lamp, is usually associated with each line, and thecircuit connections are such that each line signal glows 01' responds toa call sent over the line to which it is allotted. It is also thepractice to provide each line with one or more spring jacks and toemploy, as a means for establishing connection between any two lines, aflexible cord provided at each end with a plug adapted for insertion inone of said jacks. ith this arrangement, a subscriber can signal thecentral operator and the latter, after inserting the answering plug ofthe cord-circuit. in the jack of the calling subscriber, so as toreceive the order for connection, can then establish the desiredconnection by inserting the calling plug of the cord-circuit in the jackof the called subscriber. In addition to the foregoing, it is usual toassociate one or more supervisory or clearing-out signals with thecord-circuit, so as to enable the central operator to know when thesubscribers have finished talking and hung up their receivers. Like theline signals, these supervisory signals preferably consist of smallincandescent lamps, which are connected and arranged to light up or glowas soon as their local circuits are caused to close by the opening ofthe line circuits. As previously stated, the current, both for themicrophone transmitters at the substations and the line and supervisorysignals at the central exchange, is furnished from a common batterylocated at the central station. It is also the practice to providesuitable circuit connections whereby the in-erticn of the answering plugof the cord-circuit will operate to automatically extinguish or restorethe line signal.

Generally stated, it is the object of my invention to provide a simple,inexpensive, and highly etlicient telephone system of the foregoingcharacter.

A special object is to provide an improved circuit arrangement whichwill obviate the necessity of supplying battery current to the linethrough the cord-circuit, and to, in fact, avoid as much as possible thepassage of battery current for any and all purposes through the strandsof the cord-circuit, so as to insure against a burning out of the cords,and particularly so as to leave the cord-circuit free of battery currentduring conversation between two subscribers.

In other words, it is a particular object of my invention to provide animproved arrangement whereby no battery current is furnished directlyfrom the battery through the cord-circuit during conversation, and,furthermore, to thus avoid the use of relays in the cord strands.

It is also an object to provide certain details and features ofimprovement tending to increase the general efliciency, and to render atelephone system of this character more serviceable and reliable in use.

To the foregoing and other useful ends, my invention consists in mattershereinafter set forth and claimed.

The accompanying drawing is a diagram illustrating a telephone systemembodying the principles of my invention. In this diagram only twosubstations are shown, together with two subscribers lines and anoperators cord-circuit. It will be understood that only such instrumentsand devices are illustrated as are necessary to a full understanding ofthe operation of the invention.

It will be readily understood that the subscribers equipment orsubstation apparatus, at the substations A and B can be of any suitableknown or approved character, consistent with the principles and mode ofoperation of a common-battery or centralizedsource-of-current telephonesystem. At the central station, the switchboard apparatus comprises anoperators cord'circuit provided with plugs P and P which latter areadapted for insertion in the spring-jacks J and J these jacks beingrespectively connected with the lines leading from substations A and B.The battery 1, or other suitable centralized source of current, is, itwill be seen, permanently connected with the lines, and adapted tosupply current for both talking and signaling purposes.

Obviously, the various relays, lamp signals, condensers, impedancecoils, etc., shown in the drawings and hereinafter described, can be ofany suitable, known or approved character. The nature and functions ofthe various devices and instruments, and also the character, purpose andadvantages of the different circuit arrangements will, however, be bestunderstood by describing the operation of the system as a whole; and asillustrated and described, and assuming that the subscriber atsubstation A desires connection with substation B, the operation of atelephone system characterized by my invention is as follows: Upon theremoval of the receiver from the subscribers hookswitch at substation A,a complete metallic circuit is completed from the battery 1 through thebattery lead 2 and the impedance coils 3, thence through the lineconductor 4 to the subscribers trans mitter 5, thence through theprimary 6 of the induction coil, through the contact point 7 and thehook-switch 8, thence through the other line conductor 9, through theline re lay 10, thence through conductor 11 and impedance coil 12, andthrough conductors 13 and 14 and back to said battery. The currentflowing through this closed line circuit energizes the relay 10, causingthe latter to attract its armature. hen attracted,

. the said armature completes a local circuit from the battery 1,through the conductors 2 and 15, through the said armature 16 and itscontact point 17, thence through the line lamp 18 and the conductor 19,and through the conductors 13 and 14 to said battery. The currentflowing through this closed local circuit causes said lamp to light upor glow, and to thereby advise the central operator of the call. Uponobserving this signal, the central operator then inserts the answeringplug P in the jack J, it being observed that the latter is connectedwith the calling subscribers line. This, it will be seen, operates firstto shunt out the line relay 10, the current flowing from the linethrough the tip spring 20 of the jack, through the tip 21 of the plug,through the conductors 22 and 23, through the supervisory relay 24,through the conductor 25, through the ring contact 26 of the plug,through the ring contact spring 27 of the jack, and thence through theconductor 28 to the conductor 11, rather than from the line through thesaid relay 10. This, it Will be understood, is

for the reason that the relay 24 is of less resistance than the linerelay. The shunting automatically break the local circuit of the linelamp 18. Thus the operator in inserting the answering plug in thecalling subscribers jack automatically extinguishes or restores the linesignal. In addition to the foregoing, it will also be seen that theinsert-ion of the answering plug in this man ner serves to energize therelay 24 by reason 01: the latter being included in the line circuit,and to thus prevent the operation of the supervisory signal. In otherwords, the insertion of the answering plug practically places thesupervisory signal apparatus in condition to respond or operate when theline circuit is broken by the hanging up of the receiver at thesubstation.

It will be readily understood that the central operator can employ anyof the usual or well known means for communicating with the differentsubscribers. Upon receiving the order for connection from the callingsubscriber at substation A, the operator then inserts the calling plug Pin the jack J. This jack is connected with the line leading tosubstation B. After inserting the calling plug, the operatorthen'presses the usual ringing-key; so as to ring the subscribers bellat substation B. The. insertion of the calling plug in the jack J servesto complete the short local circuit from the battery 1 through conductor29, thence through the coil of supervisor relay 30, through the armature31, through the contact-point 32, thence through the conductors 33 and34, through the sleeve contacts 35 and 36 of the plug and jack, throughthe conductor 37 and the impedance coil 38, and thence through theconductor 39 to said battery. The current flowing through this localcircuit energizes the supervisory relay 30, causing the latter toattract its armature. The said armature when attracted closes a secondlocal circuit from the said battery through conductor 29, through thearmature 40, through the contact-point 41, thence through thesupervisory lamp 42, and through the conductor 43 to the battery. Thecurrent flowing through this second local circuit causes the lamp 42 tolight up or glow. This lamp continues to glow until the subscriber atsubstation B answers the call. When the call is answered, the linecircuit is completed from the battery 1, through the i conductor 39 andimpedance coil 38, through tthe line conductor 44 to the subscriberstransmitter 45, thence through the primary 46 of the induction coil,through the contactlpoint 47 and the hook-switch 48, thence 1 throughthe other line conductor 49, through the tip spring 50 of the jack,through the the conductor 52 and the coil of the superout of the linerelay in this way operates to I cord-strand 51 of the cord-circuit,through i has answered the call.

visory relay 53, through the conductor 54, through the ring contacts 55and 5(5 of the plug and jack, thence through conductor 57 and theimpedance coil 58 and through the conductors 59 and 14 to said battery.This, it will be seen, energizes the relay 53. causing the latter to attact its armature. The said armature when attracted breaks the localcircuit including the relay 30, causing the latter to release itsarmature. The armature 40, when released, opens the circuit of thesupervisory lamp 42. In this way, as stated, the called subscriber inanswering the call automatically extinguishes or restores thesupervisory lamp 42. The central operator then understands that thecalled subscriber It will be understood that the line relay allotted tothe line of the called subscriber is of higher resistance than thesupervisory relay 53. Hence the latter is, as stated, included in theline circuit of substation B. \Vith both line circuits thus closed thetwo subscribers are connected up for conversation. it being understoodthat the talking circuit includes the parallel line conductors, the tipand sleeve contacts of the jackets and plugs, and also the two paralleltalking strands of the cord-circuit. The condensers C and C arepreferably interposed in the talking strands of the cord-circuit. Inthis" way, the cord-circuit is divided into two inductively connectedhalves or parts. During conversation it will be seen that the batterycurrent is supplied directly to the lines through permanent connect-ionstherewith, and that no battery current passes through the cord-circuitstrands, except what current is necessary to energize the relays 24: andIt will be seen, however, that this current energizing the twosupervisory relays, is supplied from the lines, and not directly fromthe battery through the cord-circuit. In other words, duringconversation there is only a small amount of line current flowingthrough the cord-circuit, the relays 24k and 53 being practicallylocated in line shunts and not, strictly speaking, in shunts through thecord-circuit. Both terminals of each shunt are in the line.

lVhen the subscribers have finished talking and have hung up theirreceivers, the operations and circuit connections are as follows: Thehanging up of the receiver at substation A opens up the line circuit,and interrupts the flow of current through the supervisory relay 24:.This supervisory relay when thus deencrgized, releases its armature andthe latter closes the short local circuit from the battery 1. throughconductor (50, through the relay (31, through the armature 62, throughthe contact point (33, thence through conductor (14. through theconductor (55. through the sleeve contacts (iti and ()7 of the plug andjack, thence through the conductor 68 and impedance coil 3, and

through the battery lead 2 to said battery. This energizes the relaytil, causing the latter to attract its armature. The said armature whenattracted closes a second short local circuit. from the battery 1,through the conductor (30, through the armature (19, through thecontact-point 70, through the conductor 71. and the supervisory lamp 72,thence through the conductors 73 and 2 to said battery. The secondglowing of the lamp 72 advises the central operator that the subscriberat substation A has finished talking and hung up the receiver. In asimilar manner the hanging up of the re ceivcr at substation B causesthe deenergizing of the relay 53, and a consequent closing of the localcircuit including the lamp -12. The circuits through the supervisoryrelay 30 and the said lamp -12 have been previously described. Uponreceiving these clearing-out signals, the central operator thenwithdraws the plugs from the jacks and the system is then in its normalor disconnected condition. Thus, as stated, during conversation there isonly a slight amount of line current passing through the cord-circuit,and no current supply through the cord-circuit directly from thebattery. At the same time the circuit arrangement is such as to permitthe employment of the usual clearing-out signals. so as to give thecentral operator complete supervision of the connections. Iiurthermore,the advantage of shunting out the line relays is obtained without thedisadvantage of supplying battery current to the lines through thecordcircuit. In other words, the circuit arrangement has the advantageof shunting out the line relays in answering calls, so as to extinguishthe line signals, but without the necessity of thereby creating a doublesource of current to one side of the line. It often happens in systemsof this character that one of the cord-strands becomes partially brokenor injured in such manner as to, when included in a battery circuit,cause more or less arcing. This sparking or arcing of the current acrossthe break of the cord-circuit is very objectionable, as it is sure toburn out the cord. \Vith my improved arrangement. however, it will beseen that the liability of injuring the cordcircuit is greatly reduced.During conversation. as explained. there is only a small amount of linecurrent flowing through small portions of the cord-circuit. The localcircuits for the supervisory relays (31 and 30 include portions of thetalking strands, but these circuits. it will be seen, are brokenimmediately after they are closed and whi e the subscribers are talking,and consequently the flow of current is of such short duration as not.to be objectionable. It will be readily understood that the resistanceof the various resistance coils and relays can be suitably regulated oradjusted by those skilled in the art, and in accordance with theconditions of any particular case.

The various advantages of my improved circuit arrangement will bereadily apparent to those skilled in the art.

I claim as my invention 1. In a telephone system, the combination of asubscribers line, a subscribers hookswitch for opening and closing theline circuit, a threeway jack connected with the line, a line relay foroperating a line signal, said relay being connected with the tip andring contact springs of said jack, a central source of current supplyconnected with the line, an operators cordcircuit provided with athree-way plug adapted for insertion in saidjack, a supervisory relay oflower resistance than the line relay and connected with the tip and ringcontacts of the plug, a supervisory relay associated with thecordcircuit and arranged to be energized when the first mentionedsupervisory relay is deenergized by the opening of the line-circuit, anda supervisory lamp included in an open circuit having a normally openswitch-point which remains open until closed by said second supervisoryrelay.

2. In a telephone system, the combination of a subscribers line, a linerelay for operating a line signal, a three-way jack connected with theline, an operators cordcircuit provided with a three-way plug adaptedfor insertion in said jack, a supervisory relay connected With the tipand ring contacts of said plug, said supervisory relay being of lessresistance than the line relay, so as to shunt out the latter when theplug is inserted in the jack, a supplemental supervisory relay connectedand arranged to be energized when the said supervisory relay isdeenergized, and a supervisory lamp included in a local circuit hav inga normally open switch-point which remains open until closed by saidsupplemental supervisory relay.

3. A. telephone system comprising a subscribers line, a subscribershook-switch for opening and closing the line, a three-way jack connectedwith the line, a line relay connected with the tip and ring contactsprings of said jack, a battery permanently connected with the line atthe central exchange, an operators cord-circuit provided with athree-way plug adapted for insertion in said jack, a supervisory relayconnected with the tip and ring contacts of said plug and arranged to bedeenergized when the line circuit is broken by said switch, asupplemental relay associated with the cordcircuit and arranged to beenergized when the said supervisory relay is denergized, the localcircuit of said supplemental relay including the sleeve contacts of thejack and plug, and a supervisory lamp included in a local circuit havinga normally open switchpoint which remains open until closed by saidsupplemental relay.

4. In a telephone system, the combination of a subscribers line, asubscribers hookswitch for opening and closing the line circuit, abattery connected with the line at the central exchange, a line relayfor operating a line signal, a jack connected with the line and havingtwo contacts which are connected with the terminals of said line relay,an operators cord-circuit provided with a plug adapted for insertion insaid jack, a supervisory relay having its terminals connected with twocontacts of said plug, the said supervisory relay being of lessresistance than the line relay, so as to shunt out the latter when theplug is inserted in the jack, a supplemental relay associated with thecord-circuit and arranged to be energized when the supervisory relay isdeenergized by the opening of the line circuit by said switch and asupervisory lamp, the local circuit of said lamp including a normallyopen switchpoint which remains open until the supervisory relay isdeenergized and the supplemental relay energized.

5'. In a telephone system, the combination of a subscribers line, asubscribers hookswitch for opening and closing the line circuit, abattery at the central exchange permanently connected with the line, ajack permanently connected with the line at the central exchange, anoperators cord-circuit provided with a plug adapted for insertion insaid jack, a supervisory relay having its terminals connected with twocontacts of said plug, a supplemental relay arranged to be energizedwhen the supervisory relay is deenergized by the opening of theline-circuit by said switch, the local circuit of said supplementalrelay including one talking strand of the cord-circuit, and asupervisory lamp included in a local cordcircuit having a normally openswitch-point controlled by said supplemental relay, said normally openswitch-point remaining open until closed by the deenergizing of thesupervisory relay and the consequent deenergization of the supplementalrelay.

6. In a telephone system, the combination of a subscribers line, asubscribers hookswitch for opening and closing the line circuit, athree-way jack connected with the line, a battery connected with theline, a line relay having its terminals connected with the tip and ringcontact springs of said jack, a line lamp included in a local circuithaving a normally open switch-point controlled by said line relay, anoperators cord-circuit provided with a three-way plug adapted forinsertion in said jack, a supervisory relay connected with the tip andring contacts of said plug, suitable impedance coils through which.current is furnished from the battery to the line, a supplemental relayarranged to be energized when the supervisory relay is deenergized bythe opening of the line circuit by said switch, the local circuit ofsaid supplemental relay including the sleeve contacts of the plug andjack, a condenser in each talking strand of the cord-circuit, and asupervisory lamp included in a local circuit having a normally openswitch-point controlled by said supplemental relay, said normally openswitch-point remaining open until closed by the de'energizing ot' thesupervisory relay and the energizing of the supplemental relay.

7. In a telephone system, the combination of a subscribers line, asubscribers switch or circuit-changing device for opening and closingthe line circuit, a jack connected with the line, a line relay foroperating a line signal, an operators cord-circuit provided with a plugadapted for insertion in the jack, a battery at the central stationconnected with the line, line impedance coils through which current isfurnished from the battery directly to the line, and a relay normallyconnected to a talking strand and supervisory lamp associated therewith,said lamp being included in a local circuit controlled only by saidrelay, a supervisory electromagnetic device connected and arranged to becontrolled by. said switch or circuit changing device and adapted tocontrol the circuit of said relay, said local circuit remaining openuntil closed by the opening of the line-circuit and the consequentenergizing of the relay.

8. In a telephone system, the combination of a subscribers line, asubscribers switch for closing the line-circuit, a line relay foroperating a line signal, a jack connected with the line, an operatorscord-circuit provided with a plug adapted for insertion in said jack, acentral source of current connected with the line, line impedancedevices through which current is furnished from the said source directlyto said line, a normally open line shunt for shunting said line relaywhen the plug is inserted in the jack, and a relay normally connected toa talking strand and a supervisory lamp associated therewith, the localcircuit of said lamp being controlled only by said relay, and asupervisory electromagnetic device connected and arranged to becontrolled by said switch and adapted to control the circuit of saidrelay, said local circuit remaining open until closed by the opening ofthe line circuit and the muse quent energizing of the relay.

9. In a telephone switchboard, the combination of line relays,supervisory relays, plugs and jacks and suitable connections for placinthe supervisory relays in parallel with the line relays, to retire theline signals, supplemental relays having local circuits provided withnormally closed switch points controlled by the supervisory relays andnormally open switch points controlled by the said plugs and jacks, andsupervisory lamps having local circuits provided with normally openswitch points controlled only by said supplemental relays.

10. In a telephone system, the combination of subscribers lines, linerelays, a battery connected with the line through said relays, impedancecoils in series with the line relays, line lamps in parallel with saidrelays and impedance coils, said lamps having local circuits providedwith normally open switch points controlled by said relays, supervisoryrelays connected and arranged to be placed in parallel with said linerelays, supplemental relays having local circuits controlled by saidsupervisory relays, and supervisory lamps having local circuitscontrolled by said supplemental relays.

11. In a telephone system, an operators cord circuit, a pair ofsupervisory relays for each end of said cord circuit, one member of eachpair excluded from the talking circuit and controlling the other, and asupervisory lamp controlled exclusively by the other said member of eachpair, together with means under the control of the operator forproducing an audible call signal at the called subscribers station overa complete metallic ringing circuit.

12. In a telephone switch-board, the combination of line relays,supervisory relays adapted to be placed in parallel with said linerelays, supplemental relays having local circuits controlled directly bysaid supervisory relays, and supervisory lamps having local circuitscontrolled exclusively by said supplemental relays, together with acommon battery or centralized source of current supply permanentlyconnected with both sides of the lines to furnish the electric currentnecessar for talking and signaling purposes, said supplemental relaysprovided with armatures adapted when attracted to close the circuit ofthe lamps.

13. In a telephone system, the combination of line relays, a cordcircuit, supervisory relays connected with the cord circuit and adaptedto be placed in parallel with the line relays, a common battery orcentralized source of current supply permanently connected with bothsides of the lines to furnish the electric current necessary for talkingand signaling purposes, and supplemental relays directly controlled bysaid supervisory relays, provided with armatures adapted when attractedto close the circuits of the lamps, said lamp circuits having no otherpoints of control.

1.4. In a telephone system, the combination of a subscribers line, aline relay for operating a line signal, a three-way jack connected withthe line, an operators cordcircuit provided with a three-way plugadapted for insertion in said jack, a supervisory relay connected withthe tip and ring contacts of said plug, said supervisory relay adaptedto shunt out the latter when the plug is inserted in the jack, asupplemental supervisory relay connected and arranged to be energizedwhen the said supervisory relay is denergized, and a supervisory lampincluded in a local circuit having a 'nor- 10 mally open switch-pointwhich remains open until closed by said supplemental supervisory relay.

15. In a telephone system, a line relay, and a low-Wound supervisoryrelay for 15 shunting the line relay, said line relay perinanentlyconnected With the central battery, said supervisory relay normallyentirely disconnected from the battery.

16. In a telephone system, a pair of supervisory relays, a supervisorysignal controlled by said relays, and a line relay adapted to be shuntedby one of said supervisory relays to retire the line signal.

Signed by me at Chicago, Cook county, Illinois this 14th day of March1902.

HENRY P. CLAUSEN.

WVitnesses ARTHUR F. DURAND, HARRY P. BAUMGARTNER.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. G.

